Abstract: Variations of physiological characteristics of drivers have been frequently accounted for safety issues at the entrances and exits of tunnels.In order to better understand it and improve traffic safety, a field experiment is conducted to collect the illumination, real-time data of speed, and physiological data of drivers including heart rate and pupil diameter when they driving through urban tunnels.The variations and differences on physiological characteristics at the entrances and exits of urban tunnels are comparatively analyzed using mathematical statistics.Partial correlation analyses for heart rate, illumination and driving speed are conducted.A multiple linear regression model is established to study the influences of external factors on heart rate at the entrances of tunnels.The results show that heart rate has significant differences before/after entering an urban tunnel;while has no significant difference before/after leaving an urban tunnel.Pupil diameter has significant differences when entering and leaving an urban tunnel, and the value of its significance test is close to 0.The partial correlation coefficients between heart rate and illumination, heart rate and speed are -0.65 and -0.74, respectively.The degree of a fitted regression model is 0.66 when only take speed and illumination into consideration.